The present invention generally relates to a digital scanner for scanning images. More specifically, the present invention is directed to a method and apparatus for accurately scanning documents and for processing digital data to provide digital images stored in memory, which can be retrieved for printing on support material or for displaying on a display screen. The system of the present invention analyzes the scanned image data and recommends settings to improve the image quality.
In a conventional digital scanner, a light source is used to illuminate a document to be scanned. The conventional digital scanner also includes a platen glass upon which the document rests and a platen cover. The light emmitted by the light source illuminates the document and is reflected off and imaged by an optical system or lens system towards either a CCD sensor array or full width array, which converts the reflected light into electrical signals. An image processing circuit electronically registers the image, and converts the electrical signals into digital image data for use by an image output terminal, network citizen, or memory device.
A printer or other digital imaging system is typically coupled to a digital scanner for scanning an original image (e.g. document) and employs an initial step of charging a photoconductive member (photoreceptor) to a substantially uniform potential. The charged surface of the photoconductive member is exposed to a light image of the original document to selectively dissipate the charge in selected areas irradiated by the light image. This procedure records an electrostatic latent image on the photoconductive member corresponding to the informational areas contained within the original document being reproduced. The latent image is then developed by bringing a developer including toner particles into contact with the latent image. The toner particles are attracted to the latent image, forming a toner image on the photoconductive member, which is subsequently transferred to a copy sheet. The copy sheet with the toner image is then advanced to a fusing station for permanently affixing the toner image to the copy sheet.
There is a need to provide digital scanners to satisfy a wide variety of requirements based on customer environments (production equipment, office equipment, and home equipment). The traditional approach was to provide different versions of software for different customer environments to satisfy the customers"" various requirements. For example, in a production environment, image quality is considered very important and the operators (users) try to reproduce their pictorials as true to the original as possible. In this type of operating environment, the user interface might provide a magazine mode with weak background suppression and the tonal reproduction curve (TRC) would be a one-to-one TRC. In an office environment, the users frequently copy originals, which were printed by a laser printer. Therefore, these users are more concerned about the second side showing through the paper, background suppression and text quality. Therefore, a higher contrast TRC is used. Although prior art scanners can save manually inputted default settings, there is a need for a dynamic user interface to adjust the image parameters of the digital scanner to meet various customer requirements.
In more general use, where the user is not as sophisticated, the software provides settings and groups of settings in accordance with the mode of use. A typical selection of modes includes: general use default mode, text mode, coarse halftone mode, high frequency halftone mode, photograph mode, laser print/newspaper mode (coarse halftone and text), magazine mode (high frequency halftone and text), and photographic and text mode. Each of these modes include predetermined image parameter settings typically applicable to a particular mode. In addition advanced user options allow the customization of specific settings. The settings generally include: auto-background suppression level, lighter/darker and contrast setting, tone reproduction curve, filter level (sharpness/descreen level), and rendering method. With this enormous available combination of variables, most general users have great difficulty in determining which settings are right for a particular application and most will opt for the selection of default settings or a particular mode. In some instances even the selection of a suitable mode is beyond the capability of the user.
It is a purpose of this invention to provide the user, through the graphical user interface of the associated device, with recommended settings based on an analysis of the scanned image data.
The present invention addresses the need for fast, high quality digital scanners, capable of being connected to a wide array of copiers, printers, computers, networks, facsimile machines, etc., and capable of scanning and producing complex and interesting images to be stored, printed or displayed. The images may include text, graphics, and scanned or computer-generated images. Therefore, the present invention is directed toward a digital scanner capable of quickly acquiring, processing, storing and outputting digital images of documents. In order to improve the image output of the scanner, the present invention provides a system in which optimum image parameter settings are provided through the graphical user interface. The optimum settings are determined by an analysis of the scanned image data. The recommended settings could be a specific operational mode or a specific parameter depending upon the image data analysis.
Apparatus is provided that receives the image data of a scanned original or series of original documents. This image data file will include a full page histogram which contains the graphic data for a page of the document and a pixel tag histogram which identifies each pixel by its type. The histograms are processed to compare the default or current customized settings to determine compatibility between such settings and the image data. This processing results in a group of image parameter setting recommendations either by mode or by specific parameter. The user has the option to adopt the recommended settings.